非等光强正交圆偏振光对液晶偏振光栅衍射特性的影响

摘要

在实际的制备过程中,不可避免地存在非等光强正交圆偏振光制备液晶偏振光栅的情况.为了探究这种情况对制备出的液晶偏振光栅的衍射特性有何影响,本文首次从理论上,利用琼斯矩阵法推导计算出该情况下液晶偏振光栅的衍射特性.首先,计算出两束非等光强正交圆偏振光叠加后的偏振态分布.其次,利用斯托克斯参数表征叠加光场对光控取向膜的折射率响应矩阵.最后,以该响应矩阵为基础,求得液晶偏振光栅的2×2琼斯矩阵.结果表明,非等光强正交圆偏光制备的液晶偏振光栅理论上可以实现0级和1级的光强分布同时受液晶盒盒厚和入射光偏振态的调制,实现0级或±1当中任意级次衍射效率可达100%.在非等光强正交圆偏振光情况下,制备出的液晶偏振光栅依然具有良好的光学特性.%We report on the numerical analysis of liquid crystal polarization gratings (LCPGs),espe-cially those were fabricated by two incident lights with orthogonal circular polarization and different intensities,and study their general diffraction properties by Jones calculus.First,we represent the electric fields of the incident waves respectively,and figured out the interference pattern and polariza-tion properties.Second,the response matrix of the refractive index change by irradiating the polarized light was inferred and associated with the interference pattern by using the Stokes parameters.Finally,we obtained the 2×2 Jones matrix and the theoretical properties about the LCPGs based on the response matrix.The results indicate that the LCPGs fabricated by two incident lights with differ-ent intensities also can show high diffraction efficiency,about 100%,in zero order and ±1 order.